This invention relates to thermoelectric water coolers operable to provide a source of cold drinking water. More particularly, the water cooler has a thermoelectric module operable to form ice used to cool water stored in a reservoir.
Water coolers are known utilizing thermoelectric modules to freeze water in contact therewith to form ice in containers and using the ice to cool the remaining water in the containers. Usually the containers have a water supply connected thereto either from replenishable bottles or a water supply.
Examples of water coolers having thermoelectric modules to cool drinking water are disclosed by M. Alex in U.S. Pat. No. 3,088,289 and T. M. Elfving in U.S. Pat. No. 4,055,053. Elving""s cooler produces ice which is intermittently released from the thermoelectric module into a water reservoir. The energy stored in the ice cools the water while more ice is formed by the thermoelectric module.
C. P. West and D. B. Neuwen describe in International Publication No. WO 93/08432, a water cooling system having a thermoelectric module to form ice used to cool water in a reservoir. A photo-optic sensing device is used to determine when ice produced on the thermoelectric module has a predetermined mass large enough to be released into the reservoir. The sensing device generates a light beam over the thermoelectric module. As the ice grows on the thermoelectric module, the light beam is broken, which causes the electric power supply to be turned OFF. Heat is allowed to flow from a heat sink through the thermoelectric module to defrost a part of the ice immediately adjacent the thermoelectric module. This allows the ice to float towards the surface of the water in the reservoir. As soon as the ice moves out of the light beam, the electric power is again supplied to the thermoelectric module to begin generation of the next mass of ice.
The invention is a water cooler for producing ice to cool water which is efficient in use and easy to maintain. The water cooler has a reservoir for storing water. An ice producing device is mounted on the container and is operable to selectively form ice and melt the ice to allow the ice to float in the water and thereby cool the water. The operation of the water cooler is controlled with the use of a temperature sensor for sensing the temperature of the ice producing device and causing a signal when the ice producing device has attained a selected temperature for forming ice. A timer responsive to the signal of the sensor causes the ice producing device to function for a selected period of time whereby a mass of ice grows on the ice producing device. A mass of ice is released from the ice producing device and allowed to float in the water in the reservoir thereby cooling the water.
A further feature of the water cooler is the use of a sensor for determining the presence of ice on the ice producing device to control the operation of the ice producing device to melt a portion of the ice to allow the ice to float in the water in the reservoir.
The preferred embodiment of the water cooler has a container with a reservoir for storing water. A valve attached to the container is used to withdraw water from the reservoir into a glass or cup. A thermoelectric module having a cool surface and a hot surface is located in a base below the container. A heat conductor, such as a plate, is mounted on the container for transferring heat energy between the water in the reservoir and the thermoelectric module. The heat conductor has a first surface in communication with the bottom of the reservoir and the water therein and a second surface located in engagement with the cold surface of the thermoelectric module. A heat sink, located below the thermoelectric module and adjacent the hot surface thereof, transfers heat from the thermoelectric module to the surrounding environment. The dissipation of the heat is facilitated by a motor driven fan which moves air across the heat sink. The thermoelectric module is connected to a source of electric power with a control. The temperature of the heat conductor is sensed with a thermocouple or other device which causes a signal when the heat conductor has attained a selected temperature sufficient to form ice, for example, about minus 8 degrees C. A timer responsive to the sensed temperature signal maintains a supply of electric power to the thermoelectric module for a selected period of time, for example, 40 minutes, to allow a mass of ice to form on the conductor. A photoelectric sensor is located above the conductor for detecting the presence of a mass of ice when the mass of ice reaches a selected size. A control reverses the polarity of the electric power of the thermoelectric module when the sensor detects the presence of the selected size of the mass of ice whereby heat energy is transferred to the conductor causing a part of the mass of ice to melt adjacent the conductor. This allows the remaining mass of ice to float in the water and the reservoir and cool the water.
The invention includes a method of cooling water with ice in a container having a reservoir for storing water. The ice is formed by the operation of a thermoelectric module or component located adjacent a member for conducting heat energy between the water in the reservoir and the thermoelectric module. The thermoelectric module operates in response to electric power having opposite polarities which are selectively applied to the thermoelectric module. The member is cooled by the thermoelectric module energized with electric power having a first polarity. The temperature of the member is sensed with a temperature sensing device which records when the temperature is below the temperature at which water freezes, for example, minus 8 degrees C. The supply of electric power having the first polarity to the thermoelectric module to maintain the sensed temperature of the member at the temperature below the temperature at which water freezes for a selected period of time, for example, 40 minutes, to form a block of ice adjacent the member from the water in the reservoir. A timer, responsive to the temperature sensing device, operates to provide the selected period of time that the electric power is supplied to the thermoelectric module. When a selected size of the block of ice formed adjacent the plate is sensed with a photo optical sensor, the polarity of the electric power to the thermoelectric module is reversed to a second polarity thereby causing the thermoelectric module to heat the member to a temperature that melts a portion of the ice adjacent the member. This allows the remaining block of ice to free itself from the member and float in the water in the reservoir to cool the water. The polarity of the electric power supplied to the thermoelectric module is changed from the second polarity back to the first polarity when the block of ice is not sensed in the reservoir whereby the thermoelectric module operates to cool the member to form another block of ice.